Exercise Caution Toward the Heart
by friendlyneighborhoodcanarystan
Summary: When would she finally break free from the hold he had over her heart? KC Undercover/Spy AU


**Someone: Hi-**

 **Me: How fuckin dare you talk to me without having read Mountain Song!? Get the fuck outta my face and don't come back in it until you've read Mountain Song!**

 **Lol nah but all jokes aside, imma need all my fellow Canary/Killunary stans to go hit up Mountain Song: A Hunter x Hunter Story and give it the loves it deserves cuz when I tell y'all it's so damn good and that me and my friend Hannah can't stop gushing about it! I can't fuckin believe I could've had that blessing of a fic in my life if I had just filtered Canary's tag properly by selecting 'All Ratings' like sometimes I'm just deadass out here sabotaging myself.**

Canary stepped into a bar, grey eyes scanning over the sober and soon to be unsober customers sitting at various tables spread around the establishment. She felt a few curious eyes on her as she approached the counter, flashing the bartender a polite smile.

The bald, frowning man looked the woman up and down, gruffly saying as he polished a glass, "Can I help you?"

Canary didn't bother sitting down in one of the bar stools. "Yes, I'm here to see Mr. Lennerman."

The bartender hummed, setting his glass down. "Who's askin'?"

"Number 11967," Canary replied. Canary watched his eyebrows raise a fraction, realization taking over his features.

"Yeah, Mr. Lennerman's been expecting you." The man let the spy behind the counter. "Right this way, agent."

Canary followed the man as he led her through a door that had been behind the counter. The lights were flicked on, the woman taking in a room filled with boxes. She stood by silently as the suited man palmed his hand against what looked to be a normal silver sheet of metal engraved into the room's wall, the metal suddenly glowing orange in reaction. When the man took his hand back, Canary was able to see the outline of a handprint in the metal. An area of the wooden floorboards caved in, revealing a set of stairs.

The twosome silently made their way down the stairs. Canary was glad when the stairs finally came to an end.

"I gotta get back to my post," the bartender said. "Just keep straight and then make a left."

"Thank you, sir."

The hairless man nodded, turning before beginning his climb back up the stairs.

Canary walked on, soon coming to a corner in what felt like a few minutes and turning left just as the bartender had instructed. There was a door up ahead.

Canary raised a fist, rapping gently at the door. "Mr. Lennerman? It's Agent Canary Tōsen." The silence on the other side of the door made her feel uneasy, a frown now on her face. "Mr. Lennerman?" Canary gave the door a few uncertain knocks. Her frown deepened when again, there was no response.

"Barging into someone's office is the last thing I wanna do," Canary sighed. Her hand curled around the doorknob, twisting it before slowly pushing the door open. "Mr. Lennerman?"

Canary gasped, hand shooting up to cover her mouth in horror. Mr. Lennerman was…dead! The middle aged man sat at his desk, dried blood around the bullet hole in his forehead, eyes staring unseeingly forward. Who could've done this?

The door was suddenly slammed shut, Canary whirling around.

"What the hell are you doing here, Alluka's friend?"

She didn't think she'd be staring into those blue eyes again this soon. Only three months had passed, since their reunion. She suddenly felt ashamed and embarrassed, remembering how she had let him get away because she let her heart get the better of her. This was her chance to redeem herself, to bring him back home.

"What the hell am _I_ doing here?" Canary hissed, returning his glare. "What the hell are _you_ doing here, Killua?"

His eyes traced her body. Dammit, she was so tempting.

Canary rolled her eyes. Was he really checking her out _now_ of all times!? "My eyes are up here, asshole!"

Killua met her eyes, smirking. "So they are."

God, she didn't have time for his damn games! Her gaze turned accusing and angry. "Did you kill Mr. Lennerman?" His silence told her all she needed to know. "What the hell is wrong with you!?"

Killua shrugged, hands finding their way into his pockets. "Wouldn't be the first time I've killed someone. I _was_ an assassin, after all."

Canary let out a frustrated noise. How could he be so nonchalant!? "Killua, you're making yourself an enemy of the agency!"

"I know."

Canary laughed hollowly, looking off to the side. "I can't fuckin believe you sometimes."

He should get going. Illumi would start getting impatient soon. "How's Alluka?"

Canary let out another laugh, this one dripping in bitterness. "Oh, so _now_ you want know how your sister is doing? _Now_ , even after I gave you the chance to three months ago."

Killua glared at her. "How long are you gonna keep pretending like I don't care about Alluka?"

"You left, Killua!" Canary cried, voice cracking. "You left without saying a damn word to her, so excuse me for thinking you don't give a shit about her."

"Well, you're wrong," Killua said resolutely. "It isn't just Alluka you think I don't care about, right?"

He was taking steps toward her now, Canary backing up with every pace he took. She sucked in air when she made contact with Mr. Lennerman's desk, tightly gripping the edge of the deceased man's desk as she looked away from the handsome man now standing directly in front of her. He used two fingers to lift her chin, heart speeding up at the affectionate look in his eyes.

"I care about you, Canary," Killua declared. "A lot."

She wouldn't bend to him this time. "Tell me what's going on, Killua. Tell me why you left. Look, if you've gotten yourself into some kind of trouble then I can—"

"You _can't_ help me, Canary," Killua interrupted, voice and eyes firm. "And even if you could, I wouldn't let you."

Canary scowled up at him. "Why!?"

He slowly dragged the back of his hand down on her face, eyes softer. "Because the last thing I want to happen is for you to get hurt."

"I can take care of myself," Canary snapped. "And for the record, I don't take orders from you."

Killua laughed, smiling. "You could've never made it as an assassin. You're too soft." He cupped her cheek. "I've always liked that about you, though."

Canary resisted relaxing into his soft touch.

"Wanna know a secret?" He grinned at the hint of curiosity in her eyes. "I was gonna tell you how I felt on graduation day." He paused, giving her a bit of time to process the information. She stayed quiet, lips in a thin line but face betraying obvious surprise. "I mean, I'm six years late but whatever!" He smiled, taking her pretty face in his hands. "I'm in love with you, Canary Tōsen."

She didn't know what to say, overwhelmed by both his confession and the love in his eyes. She should've stopped him from closing the distance between their lips when she had the chance. How could she let him have this big a hold on her? Maybe if she were blind like her father, then he'd be easier to resist. At least then she wouldn't have to be swept into those cerulean eyes, wouldn't have to deal with them weakening her resolve.

He had wanted to experience the sweet taste of her lips again the moment she walked through that door. Had it really on been three months? It felt longer than that. God, he wanted her, wanted to feel her beneath him again, wanted to make her experience the greatest pleasure. He didn't know when they'd see each other again so he kissed her with all he had, wanting her delectable taste to never fade from his tongue. He clutched at the back of her shirt, resisting the strong urge to undress her right here and now. He couldn't, though. He was already pushing it just by kissing her, after all. He knew he'd lose himself in her body if he went any further.

She could barely get a breath in when their mouths would routinely come undone momentarily, Killua's kisses rough and desperate. He was holding her so close to him, his nails digging into the fabric of her shirt. Waiting for him to rip it off, along with the rest of her clothes was agonizing. She hated feeling so impatient, hated that she wanted to feel Killua's hands on her bare skin again. For god's sake there was a dead man sitting right behind them and yet, here she was making out with Killua. She needed to put a stop to this, to push him away but her body just wouldn't listen to reason, her legs wrapping themselves around his waist.

There was a vibration in his back pocket. Shit! Canary moaned, multiple ways of making her moan even louder crossing his mind. He finally pulled back, wishing he had more time as he stared hungrily at her swollen lips. He made their foreheads touch. "You drive me crazy."

Canary averted her eyes, feet touching the ground again as she unwrapped her legs from around his waist. Her mission would go uncompleted now all thanks to Killua and _this_ is what she does. He made her act like such a damn fool.

The back of his hand brushing lightly against her cheek was all it took for her to look back at him, the conflicting emotions of yearning and hesitance in her eyes. He leaned in again, pausing after Canary closed her eyes in anticipation, using her unawareness as an opportunity to pinch a pressure point in the back of her neck. Canary went limp in his arms, Killua hoisting the unconscious woman into his arms, sighing as he stared at her face.

"Ah, so this is what's been keeping you here longer than expected."

The hollow, emotionless voice made his eyes narrow. Killua turned around, eyes having gone cold as he stared at his older brother standing in the doorway. He watched Illumi look at the woman in his arms, wanting to pluck those empty eyes out of their sockets for even daring to look at Canary.

"My offer still stands, Kil," Illumi said, smiling chillingly. "I could tamper with her and then you can sleep with her to your heart's content."

Killua bit back a growl. _Tamper_ with her? The fuckin bastard! Killua glared at the man, brushing past him.

"She's quite beautiful," Killua heard Illumi say, the cruel man at his heels. "I can see why you're so infatuated with her."

Netero's office was the last place Canary wanted to be at right now. She wanted to be curled up in her bed at home right now. His lips practically bruising her own as he kissed her with so much passion, their bodies pressed so unbelievably close, his eyes mirror her exact wants, his confession… It was all still fresh in her mind, all still so vivid.

"I know you and Killua have history."

He had no idea how lightly he was putting that. Canary looked up at the elderly man, his elbows propped up on his desk, his hands folded together. There was sympathy in his eyes.

"But he's murdered a longtime informant of ours. Killua is now an _enemy_."

 _I'm in love with you, Canary Tōsen._

There was a painful twist in her gut, Canary swallowing shakily. "Yes, sir."


End file.
